Inverse design of high-Q wave filters in two-dimensional phononic crystals by topology optimization

TL;DR

This paper presents a topology optimization method for designing high-Q wave filters in 2D phononic crystals, achieving ultra-high quality factors without additional coupling media, and enabling multi-channel filtering and wave control.

Contribution

It introduces a novel topology optimization approach for phononic crystal cavities that yields ultra-high-Q filters with symmetric resonances, applicable to various acoustic and opto-mechanical devices.

Findings

Achieved ultra-high-Q filters through cavity topology optimization.

Enabled multi-channel filtering and T-splitter functionalities.

Most optimized filters exhibit Fano resonances near resonance frequencies.

Abstract

Topology optimization of a waveguide-cavity structure in phononic crystals for designing narrow band filters under the given operating frequencies is presented in this paper. We show that it is possible to obtain an ultra-high-Q filter by only optimizing the cavity topology without introducing any other coupling medium. The optimized cavity with highly symmetric resonance can be utilized as the multi-channel filter, raising filter and T-splitter. In addition, most optimized high-Q filters have the Fano resonances near the resonant frequencies. Furthermore, our filter optimization based on the waveguide and cavity, and our simple illustration of a computational approach to wave control in phononic crystals can be extended and applied to design other acoustic devices or even opto-mechanical devices.